Richard,
This morning (Sunday) I unexpectedly found myself within a reasonable distance of the Civic Centre, with some spare time available.  So knowing that the West Glamorgan Archives only work Monday to Friday, I called instead, into the Civic Centre branch of the library service and had a quick look at their local Newspaper Archive and found the following news item in the "South Wales Daily Post, Tuesday, March 8, 1904" FATAL ACCIDENT AT
FFORESTFACH
------
COLLIER KILLED BY A FALL AT
GENDROS PIT
Fforestfach,  on  Tuesday afternoon.   A fall
took   place,    Benjamin   Thomas,   collier,
Carmarthen Road, Fforestfach,  was killed on
the spot.  Thomas  who  was 35 years of age,
leaves  a  widow  and  three  young  children. 
   Deceased recently acted as overman during 
the  absence  of  the overman with  a  broken
leg.   On Monday  night  he  took part  in  the
voting for the election of Parish Councillor.
    Only   twelve   months   ago   last   August 
Thomas's  brother  lost  his  life  in  the  same
colliery.
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I trust that although you didn't specifically ask for a newspaper search, that you find the above to be of interest.
Needless to say, I shall be returning to the Civic Centre as soon as is practical to complete the original commitment.
JohnG_Swansea.